DC (DC/DC) converters are widely used in electrified railway transportation, electrical power system, renewable energy generation, energy storage system, high-power transmission, and the like fields. Especially in the field of high-power applications, in order to increase power capacity or meet requirements of high-current operation of a system, modular parallel connection of DC converters has become a development trend.
EMI (Electro-magnetic interference) filters used to suppress electromagnetic interference in DC converters play an important role in product performance, cost and operational reliability. Conventional DC converters are equipped with EMI filters at input and output sides of the circuit topology respectively. However, such configuration has troubles in design or application for some DC converters, such as the current circulation problem in multiple modules in the parallel application and magnetic saturation risk of EMI common mode inductors.
Therefore, it is necessary to improve EMI filters design in DC-DC converters.